热循环频率对铸态Zn-Al合金相变超塑性的影响  

Effects of thermal cycle frequency on transformation superplasticity of Zn-Al cast alloy

作　　者：石志强[1] 李世春[1] 刘宇慧[1] 

机构地区：[1]石油大学机电工程学院,山东东营257061

出　　处：《石油大学学报（自然科学版）》2004年第3期69-71,74,共4页Journal of the University of Petroleum,China(Edition of Natural Science)

基　　金：国家自然科学基金资助项目 ( 5 98710 3 1)

摘　　要：用恒载荷蠕变法研究了热循环频率对质量分数为 5 %的铝的铸态Zn Al合金相变超塑性的影响。研究结果表明 ,在温度为 2 0～ 35 0℃循环条件下进行拉伸时 ,铸态Zn Al合金的延伸率能超过 10 0 % ,呈现相变超塑性特征。改变热循环频率对铸态Zn Al合金的相变超塑性有很大影响。若保持循环温度和外加载荷不变 ,随着热循环频率的提高 ,铸态Zn Al合金的相变超塑性延伸率增大 ,而准稳态蠕变阶段的应变速率则有所降低。Zn Al铸态合金的这种相变超塑性与共析相变过程中新、旧相间的界面行为有很大关系 ,相变过程中产生的内应力在外应力的偏置作用下使新、旧相界面间的Zn Al合金发生牛顿粘滞性流动 ,而界面间的原子扩散对热循环中Zn Al合金的变形起着重要的协调作用。The effect of thermal cycle frequency on the transformation superplasticity of Zn-Al cast alloy containing alumni with a fraction of 5 percent was investigated with the constant load creep test. The results show that under the condition of thermal cycle tension test at 20 ～ 350℃, the tensile elongation percentage of the Zn-Al cast alloy can exceed 100 percent, and the alloy exhibits transformation superplasticity clearly. The thermal cycle frequency has an obvious effect on the transformation superplasticity of Zn-Al alloy. When the thermal cycle temperature range and external load keep constant, the superplastic elongation percentage will increase, while the strain rate in the quasi-steady deformation state will decrease with increasing thermal cycle frequency. The transformation superplasticity of Zn-Al alloy is related to the characteristics of the interphase boundaries between new and origin phases in the eutectoid transition region. In the thermal cycle phase transition process, Newton viscous flow of Zn-Al alloy occured in the interphase boundaries between new and origin phases. The diffusion of atoms between the interphase boundaries had a coordinated effect on the deformation of Zn-Al alloy in the thermal cycle process.

关 键 词：ZN-AL合金 延伸率 热循环频率 恒载荷蠕变法 金属材料 

分 类 号：TG146.13[一般工业技术—材料科学与工程] TG111.7[金属学及工艺—金属材料]